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Title: | 高分子空乏層對於電解質黏彈流體擴散滲透流之影響 Diffusioosmotic Flows of Viscoelastic Electrolytic Liquids including Polymer Depletion Layer Effects |
Authors: | Bang-Li Wu 吳邦莉 |
Advisor: | 黃信富(Hsin-Fu Huang) |
Keyword: | 擴散滲透流,完整界面靜電條件,馬克士威應力張量,范善─譚納(PTT)模型,高分子空乏層,威森堡數, diffusioosmotic flows,full interfacial electrostatics,Maxwell stress tensor,Phan-Thien-Tanner (PTT) model,polymer depletion layer,Weissenberg number, |
Publication Year : | 2017 |
Degree: | 碩士 |
Abstract: | 中文摘要
隨著實驗式晶片與微型全分析系統成為了近代具發展潛力的整合型產業,微流道擴散滲透流的應用也逐漸受到重視。考量到實務應用上,微流體裝置的工作流體多為具黏彈特性的非牛頓流體,因此本文著重在探討黏彈流體模型對於擴散滲透流之影響,更進一步探討流體中高分子聚合物可能對流道產生的物理影響,包括:壁面附近高分子空乏層的存在與空乏層─高分子層交界面上的完整界面靜電條件。吾人由描述離子濃度與電荷分佈的泊松─波茲曼方程式來求得電雙層電位場,並引入范善─譚納(Phan-Thien-Tanner, PTT)模型本構方程式、牛頓流體模型本構方程式與流體運動方程式,依序解出壓力場、誘導電場、流體剪應力、流體剪應變率、速度場與體積流率。其中,影響流動表現的參數包含:正負離子擴散係數差、壁面電位、雙液界面電位不連續、雙液界面電荷密度、高分子的黏彈性、空乏層厚度、牛頓流體模型之德拜常數、內外層德拜常數比值、內外層導電度比值、高分子聚合物黏滯係數和牛頓流體黏滯係數比值,以及水平鉛直方向電場強度比值。最後針對求得的物理量進行參數分析和討論。另外,吾人也發現空乏層與高分子層交界面上若存在界面跳躍電位與界面電荷密度,兩者對流場的影響遠比其它變異因子來的大。 英文摘要 Diffusioosmotic flows (DOF) are widely applied in “Lab-on-a-chip” and micro-total analysis systems devices nowadays due to their potentials in research and industrical development. In addition, as the working fluids found in the microfluidic applications are mostly non-Newtonian viscoelastic liquids, this study is therefore aimed at discussing the influence of liquid viscoelasticity, polymer depletion layers, and full interfacial electrostatic effects on the flow responses of diffusioosmotic flows. Since near wall electric potentials are established under the presence of the electrical double layers, we shall describe the double layers potectial via the Poisson-Boltzmann equation. Based on the Phan-Thien-Tanner constitutive model, Newtonian constitutive model, and the basic equations describing this fully-developed incompressible fluid flow, the pressure fields, the induce electric fields, the shear stresses and shear strains in fluids, the velocity fields, and the flow rates can be obtained. The obtained semi-analytical solutions allow us to investigate variations in the flow responses with respect to the wall zeta potential, diffusivity difference parameter, interfacial potential jumps, surface charge densities, rheology of polymer solutions, thickness of depletion layers, Debye thickness ratio, permittivity ratio, ratio of polymer viscosity coefficient to the Newtonian viscosity, and the ratio of the vertical to horizontal electric field. Finally, we found that the flow behavior and responses are significantly altered when the interfacial potential jumps and surface charge densities are included in the analysis. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/77754 |
DOI: | 10.6342/NTU201702316 |
Fulltext Rights: | 未授權 |
Appears in Collections: | 機械工程學系 |
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ntu-106-R04522117-1.pdf Restricted Access | 2.47 MB | Adobe PDF |
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